Easy Network Service Monitor 

Easy to use and low cost tool for network, applications and services monitoring, fault identification, notification and reporting as well as service level agreement monitoring and reporting.
server service level agreement sla network monitor network applications network troubleshooting fault management network management network performance

Analyse It 

Analyse It is a SNMP network interface utilization and error, graphical reporting tool. Enables network availability, performance, reliability and utilization reporting.
snmp tool monitor report network graph analysis free response time graphical ip accounting mib cisco nortel